What is Mass Hysteria?

Anyone Can Be a Victime of Mass Hysteria

Man holding back cheering crowd
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Mass hysteria is a form of groupthink, in which many people behave or react to something real or imagined in an uncontrolled or extreme way. In mass hysteria, the group members all develop a common fear that spirals into a massive disruption and the threat's actual risk must be disproportionate to the reaction of the group.

Mass hysteria spreads through sight, sound, smell or conversation. The group members feed off each other's emotional reactions, causing the panic to escalate.

Other names for mass hysteria include mass psychogenic illness and mass sociogenic illness.

Some riots, witch hunts, and other events are linked to mass hysteria. The radio broadcast War of the Worlds and the TV movie Without Warning both spawned outbreaks of mass hysteria.

Who is More Likely to Be a Part of Mass Hysteria?

The research on mass hysteria shows your personality type won't make you more or less likely to get caught up in groupthink. There are no predominant physical, social or psychological characteristics that make you more likely to groupthink. With the right combination of fear and anxiety, all people are capable of getting caught up in mass hysteria.

Complications of Mass Hysteria

Mass hysteria can cause unnecessary complications in an already chaotic situation for emergency response services.

For example, if there's a toxic chemical spill at a nearby factory, emergency rooms may fill with casualties.

Some will be victims of poisoning, while others feel sick, but aren't. In these situations, it can be difficult for health care workers to prioritize patients and discern who is ill and who's having psychosomatic symptoms, resulting in a lower quality of care.

Odor and Mass Hysteria

Mass hysteria caused by an odor or a perception of an odor is not uncommon in cases of mass hysteria associated with contaminated water, nuclear accidents or chemical spills.

First, a group of people experiences trauma after an environmental incident. Then someone smells something, develops symptoms (such as a headache or vomiting) and reports it. The report is made public and then other people start reporting similar symptoms. In the end, there was no odor or the odor is known to not cause health issues.

Mass Hysteria and the Ebola Virus

The recent outbreak of the Ebola virus in Africa caused mass hysteria in the United States. New Jersey Governor Chris Christie irrationally held a nurse against her will in a tent even though she had already tested negative for the virus after treating patients in West Africa.

Many healthcare experts asserted their professional opinion that quarantine was unnecessary, but some citizens joined in the mass hysteria and agreed with the governor anyway.

Mass Hysteria and Witchcraft

There are numerous cases of mass hysteria throughout history propelled by the dominant, although misguided, sociocultural concerns of the time. A prominent example from the 15th to 19th centuries highlights how strong Christian beliefs that witchcraft was real prompted widespread panic.

When factory workers complained of convulsions and neurological issues, the public blamed these symptoms on witches and demonic possession, instead of environmental toxins in the workplace.

This misdiagnosis led to an erroneous paranoia of witches, which resulted in persecution and sometimes execution of those accused.


NBC News: New Jersey Gov. Chris Christie Defends Quarantine of Nurse Kaci Hickox (2014)

Balaratnasingama and Janca. Current Opinion in Psychiatry: Mass Hysteria Revisited (2006)

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